Humidification system for fuel cell and fuel cell system

Abstract

The present invention provides a humidification system for a fuel cell, the humidification system being configured to humidify a gas flow supplied to the fuel cell. The humidification system comprises: an injection unit (1) configured to inject liquid water; and a mixing unit (2) connected to the injection unit (1), the mixing unit (2) being configured to mix the water injected by the injection unit (1) with the gas flow flowing through the mixing unit (2), wherein the mixing unit (2) comprises a mixing chamber (21) and a flow guide element (22) arranged in the mixing chamber (21), the flow guide element (22) being configured to form a swirling flow in the gas flow flowing through the mixing chamber (21). The present invention also provides a fuel cell system. By means of the present invention, the humidification system for the fuel cell can be made to have a smaller volume.

Description

Technical Field

[0001] The present invention relates to a humidification system for a fuel cell and a fuel cell system. Background Art

[0002] Fuel cells are electrochemical power generation devices that convert chemical energy directly into electrical energy. Because they consume no fossil fuels and produce virtually zero emissions, they have garnered widespread attention and development as a next-generation energy source. Among various fuel cell types, proton exchange membrane fuel cells (PEMFCs) are a widely used type, offering key advantages such as low operating temperatures and rapid startup, making them particularly suitable for use in motor vehicles.

[0003] In a proton exchange membrane fuel cell, hydrogen is used as the fuel and air or pure oxygen as the oxidant. A polymer membrane acts as the electrolyte, conducting protons (hydrogen ions) generated in the anode region to the cathode region. The proton exchange membrane must maintain a high level of humidity to ensure good proton conductivity. This is because ionic conductivity is particularly dependent on hydration levels; greater hydration capacity results in higher conductivity and, therefore, a more efficient cell.

[0004] Humidifiers are currently known for increasing the humidity of air supplied to fuel cells. This increases the moisture content of the air before it is supplied to the fuel cell stack, thereby increasing the humidity of the proton exchange membrane. Typically, this air is humidified using a porous material.

[0005] However, existing humidifiers for fuel cells have the disadvantage of being relatively large. Summary of the Invention

[0006] The object of the present invention is to provide an improved humidification system for a fuel cell and an improved fuel cell system, wherein the humidification system for a fuel cell has a smaller volume.

[0007] According to a first aspect of the present invention, a humidification system for a fuel cell is provided, wherein the humidification system is configured to humidify a gas flow supplied to the fuel cell, and the humidification system includes: an injection unit configured to inject water; and a mixing unit connected to the injection unit, wherein the mixing unit is configured to mix the water injected by the injection unit with the gas flow flowing through the mixing unit, wherein the mixing unit includes a mixing chamber and a guide element arranged in the mixing chamber, wherein the guide element is configured to cause the gas flow flowing through the mixing chamber to form a vortex.

[0008] According to an exemplary embodiment, the flow guide element comprises a plurality of fins distributed in a circumferential direction around the flow guide element axis, the fins extending from the radial outside toward the flow guide element axis, and the fins being inclined relative to the flow guide element axis.

[0009] According to an exemplary embodiment, the flow guide element comprises a cylindrical wall, and the fins each extend radially inward from at least one axial edge of the cylindrical wall.

[0010] According to an exemplary embodiment, the flow guide element is configured at least approximately parallel to the flow guide element axis and extends circumferentially around the flow guide element axis.

[0011] According to an exemplary embodiment, the mixing unit comprises a plurality of flow guide elements, which are distributed around the flow guide element axis at a distance from one another.

[0012] According to an exemplary embodiment, the mixing unit comprises a collision element which is arranged in the mixing chamber such that the spraying direction of the spraying unit is directed towards the collision element, the collision element having a collision surface transverse to the spraying direction.

[0013] According to an exemplary embodiment, the crash element is arranged on the flow guide element or is formed integrally with the flow guide element.

[0014] According to an exemplary embodiment, the spraying unit is arranged such that the spraying direction is towards the flow guide element.

[0015] According to an exemplary embodiment, the humidification system includes a return unit configured to draw water from the spray unit.

[0016] According to a second aspect of the present invention, there is provided a fuel cell system comprising the humidification system for a fuel cell according to the present invention.

[0017] According to the present invention, a mixing unit capable of creating a swirling gas flow allows the water mist and gas flow to be thoroughly mixed by the swirling flow. This facilitates vaporization of droplets in the water mist and their uniform distribution within the gas flow. Thus, a compact humidification system can efficiently achieve thorough mixing of water and gas flow and promote water vaporization. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be described in more detail below with reference to the accompanying drawings, so that the principles, features and advantages of the present invention can be better understood.

[0019] Figure 1 A schematic diagram of a humidification system for a fuel cell according to an exemplary embodiment of the present invention is shown;

[0020] Figure 2 Schematically shows a cross-sectional view of a mixing unit in a humidification system according to an exemplary embodiment of the present invention;

[0021] Figure 3 schematically shows a perspective view of a flow guide element according to an exemplary embodiment of the present invention;

[0022] Figure 4 Schematically shows a perspective view of a mixing unit in a humidification system according to an exemplary embodiment of the present invention;

[0023] Figure 5 Schematically shows the Figure 4 a perspective view of a mixing unit of an exemplary embodiment similar to the embodiment shown; and

[0024] Figure 6 A schematic diagram of a humidification system for a fuel cell according to an exemplary embodiment of the present invention is shown. DETAILED DESCRIPTION

[0025] In order to make the technical problems, technical solutions and beneficial technical effects to be solved by the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and multiple exemplary embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the scope of protection of the present invention.

[0026] In this context, "at least substantially parallel" is understood to mean within 20°, within 15°, within 10°, within 5°, within 3°, within 2°, or within 1° of being substantially parallel, or substantially parallel.

[0027] Figure 1 A schematic diagram of a humidification system for a fuel cell according to an exemplary embodiment of the present invention is shown. The humidification system is configured to humidify a gas flow supplied to the fuel cell, particularly an air flow supplied to the cathode side of the fuel cell. The fuel cell is particularly a proton exchange membrane fuel cell that uses hydrogen as fuel and air as an oxidant. The gas flow may be supplied via a compression device. The fuel cell may be used, for example, in a motor vehicle.

[0028] In this embodiment, the humidification system may include: a spray unit 1 configured to spray water; and a mixing unit 2 connected to the spray unit 1, configured to mix the water sprayed by the spray unit 1 with a gas flow passing through the mixing unit 2. The spray unit 1 may include a nozzle that sprays water into the mixing unit 2 in the form of a water mist. The mixing unit 2 includes a mixing chamber 21 and a flow guide element 22 configured to form a swirling flow in the gas flow passing through the mixing chamber 21. The water sprayed by the spray unit 1 may be liquid water or gaseous water vapor. Figure 1The arrows schematically illustrate the direction of gas flow. The mixture of water mist sprayed by the spray unit 1 and the gas flow is thoroughly mixed through swirling flow. This helps vaporize droplets in the water mist to form gaseous water, which is evenly distributed throughout the gas flow. This mixing unit is compact and highly efficient. Thus, a compact humidification system can efficiently achieve thorough mixing of water and gas flow, promoting water vaporization.

[0029] like Figure 1 As shown, the spray unit 1 can be arranged so that the spray direction is toward the flow guide element 22. This is conducive to the thorough mixing of water and gas flow, because it can avoid the water mist being directly sprayed onto the wall of the mixing unit 2. In addition, this is conducive to the compact layout of the humidification system.

[0030] According to this embodiment, the humidification system may further include: a water reservoir 3 for storing water; a supply unit 4 configured to supply water to the spray unit 1; and a controller 5 configured to control the spray unit 1 and / or the supply unit 4.

[0031] The supply unit 4 may include a supply pump, which is implemented as a diaphragm pump, for example. The supply unit 4 may pump water from the water reservoir 3 via the supply pump and supply the water to the spraying unit 1 at an increased pressure.

[0032] The controller 5 enables metered water injection as needed. The controller 5 can control humidification based on a sensor 51 for measuring air flow. For example, the controller 5 can be connected to a humidity sensor arranged downstream of the mixing unit 2 for measuring the humidity of the gas flow and perform control based on a signal from the humidity sensor. Alternatively or additionally, the controller 5 can control humidification based on, for example, an electrical signal from a fuel cell unit.

[0033] In addition, the humidification system may include a heater 6 for heating the water to be sprayed. The heater 6 may be connected between the supply unit 4 and the spraying unit 1. Heating the water to be sprayed is beneficial to the vaporization of the water.

[0034] Figure 2 Schematically shows a cross-sectional view of a mixing unit 2 in a humidification system according to an exemplary embodiment of the present invention, wherein arrows schematically show the flow direction of the gas flow. Figure 2 As shown, the guide element 22 can be arranged in the mixing chamber 21. The water and gas flow sprayed by the spray unit 1 is guided by the guide element 22 to rotate, thereby forming a vortex of water mist and gas flow in the mixing chamber 21. The guide element 22 can be designed to have any structure suitable for causing the air flow flowing through it to form a vortex, that is, the guide element 22 is configured as a vortex guide.

[0035] Figure 3A perspective view of a flow guide element 22 according to an exemplary embodiment of the present invention is schematically shown. In this embodiment, the flow guide element 22 includes a plurality of fins 221 distributed circumferentially around the flow guide element axis, with the fins 221 extending radially outward toward the flow guide element axis. The flow guide element 22 may include at least two, at least three, at least four, or at least five fins 221, for example, nine fins 221. The fins 221 may be evenly distributed circumferentially.

[0036] The vanes 221 are inclined relative to the axis of the flow-guiding element. The vanes 221 form an angle with the axis of the flow-guiding element greater than 0° and less than 90°. In other words, the vanes 221 are neither perpendicular nor parallel to the axis of the flow-guiding element. Each vane 221 may form the same angle with the axis of the flow-guiding element. Gas flow striking each vane 221 is deflected by these vanes 221. The deflection by all the vanes 221 creates a swirling flow.

[0037] The flow guide element 22 may further include a cylindrical wall 222, which may be configured to be installed in the mixing chamber 21. A plurality of fins 221 may extend radially inward from the axial front edge and / or rear edge of the cylindrical wall 222. It should be understood that if sufficient swirl can be generated, the fins 221 may only be provided on one axial edge of the cylindrical wall 222.

[0038] Figure 4 A perspective view of a mixing unit 2 in a humidification system according to an exemplary embodiment of the present invention is schematically shown. In this embodiment, the mixing unit 2 includes a cylindrical mixing chamber 21. The mixing chamber 21 includes a first end wall 211, a second end wall 212, and a surrounding side wall 213 connecting the first and second end walls 211, 212. The first and second end walls 211, 212 are arranged substantially parallel to each other and spaced apart. At least one, and here four, air inlets 214 are formed in the first end wall 211, and at least one air outlet 215 is formed in the second end wall 212. It should be understood that the air inlet 214 and the air outlet 215 may also be provided at other locations in the mixing chamber 21, such as in the side wall 213. A spray opening may be formed in the side wall 213 of the mixing chamber 21. The spray unit 1 is connected to the mixing chamber 21 at the spray opening and sprays water into the mixing chamber 21 along a spray direction.

[0039] A flow guide element 22 may be disposed in the mixing chamber 21. The flow guide element 22 is configured to be at least approximately parallel to the flow guide element axis and to extend circumferentially around the flow guide element axis. The flow guide element 22 may be configured as a plate that is curved or bent around the flow guide element axis. The flow guide element 22 guides the gas flow from the gas inlet 214 to the gas outlet 215, forming a swirling flow. The water injected by the injection unit 1 forms a swirling flow with the gas flow, thereby being thoroughly mixed with the gas flow.

[0040] The flow guide element 22 can be arranged between the first end wall 211 and the second end wall 212, with the flow guide element axis perpendicular to the first end wall 211. In particular, the flow guide element 22 can extend from the first end wall 211 along the flow guide element axis to the second end wall 212. The flow guide element 22 can extend from the side wall 213 and can extend circumferentially around the flow guide element axis by at least 60°, at least 90°, at least 180°, or at least 270°. The flow guide element 22 can be arranged eccentrically relative to the mixing chamber 21.

[0041] In another embodiment, the mixing unit 2 may include a plurality of flow guiding elements 22, each of which is configured to be at least substantially parallel to the flow guiding element axis and extend circumferentially around the flow guiding element axis. The plurality of flow guiding elements 22 may be distributed circumferentially around the flow guiding element axis at intervals from each other.

[0042] It should be understood that the guide element 22 may be designed as other structures suitable for causing the airflow flowing through it to form a swirl, for example, as a structure that is transverse to the axis of the guide element and extends helically around the axis of the guide element.

[0043] Figure 5 Schematically shows the Figure 4 The embodiment shown is a perspective view of a mixing unit 2 of an exemplary embodiment similar to the embodiment shown, wherein the mixing unit 2 is cut away to illustrate its internal structure. In this embodiment, the mixing unit 2 includes a collision element 23, which is arranged in the mixing chamber 21 such that the spray direction of the spray unit 1 is directed toward the collision element 23. The collision element 23 has a collision surface transverse to the spray direction. The water sprayed by the spray unit 1 can collide with the collision surface of the collision element 23. As a result, larger droplets are transformed into smaller droplets that are more easily mixed with the gas flow. The collision surface can be perpendicular to the spray direction, thereby facilitating the collision of the sprayed water into smaller droplets.

[0044] like Figure 5 As shown, the collision element 23 can be arranged on the flow guide element 22, or can be formed integrally with the flow guide element 22. A plurality of collision elements 23 can be formed on one flow guide element 22. The collision element 23 can be configured as a collision tongue extending from the flow guide element 22.

[0045] It should be understood that the collision element 23 may also be provided with a different Figure 5 Other flow guide elements 22 of the structure shown are used together.

[0046] Figure 6A schematic diagram of a humidification system for a fuel cell according to an exemplary embodiment of the present invention is shown. In this embodiment, the humidification system includes a reflux unit 7 configured to draw water from an injection unit 1. This reflux unit 7 can drain the water from the injection unit 1 as needed, preventing the water from freezing due to low temperatures within the injection unit 1 and potentially damaging the humidification system. For example, the controller 5 can control the reflux unit 7 to drain the water from the injection unit 1 based on an electrical signal from the fuel cell unit.

[0047] The return unit 7 may be configured to suck water from the spray unit 1 and discharge it to the water reservoir 3. The return unit 7 may include a return pump, which may be implemented as the same pump with a reversible pumping direction as the supply pump or as another pump.

[0048] Although specific embodiments of the present invention are described in detail herein, they are provided for illustrative purposes only and should not be considered to limit the scope of the present invention. Various substitutions, changes, and modifications may be conceived without departing from the spirit and scope of the present invention.

[0049] Reference Signs List

[0050] 1 Injection unit

[0051] 2 Mixing units

[0052] 21 Mixing Chamber

[0053] 211 First end wall

[0054] 212 Second end wall

[0055] 213 sidewall

[0056] 214 air intake

[0057] 215 air outlet

[0058] 22 flow guide element

[0059] 221 Wing

[0060] 222 cylindrical wall

[0061] 23 collision element

[0062] 3 Water storage tank

[0063] 4 Supply units

[0064] 5 Controller

[0065] 51 sensors

[0066] 6 Heater

[0067] 7 Reflux Unit

Claims

1. A humidification system for a fuel cell, the humidification system being configured to humidify a gas flow supplied to the fuel cell, the humidification system comprising: A spray unit (1), the spray unit (1) being configured to spray water in the form of water mist; A mixing unit (2) connected to the injection unit (1), the mixing unit (2) being configured to mix water injected by the injection unit (1) with a gas flow flowing through the mixing unit (2), characterized in that the mixing unit (2) comprises a mixing chamber (21) and a guide element (22) arranged in the mixing chamber (21), the guide element (22) being configured to cause the gas flow flowing through the mixing chamber (21) to form a swirl, wherein the guide element (22) is configured to be at least approximately parallel to an axis of the guide element and to extend circumferentially around the axis of the guide element, a plurality of rows of collision tongues being formed on the guide element (22), each of the plurality of rows of collision tongues extending from the guide element (22) in a direction deflected relative to the guide element (22).

2. The humidification system for a fuel cell according to claim 1, wherein: The mixing unit (2) comprises a plurality of flow-guiding elements (22), which are distributed around a flow-guiding element axis at a distance from one another.

3. The humidification system for a fuel cell according to claim 1 or 2, wherein: The collision element (23) is arranged on the flow guide element (22) or is formed integrally with the flow guide element (22).

4. The humidification system for a fuel cell according to claim 1 or 2, wherein: The spraying unit (1) is arranged so that the spraying direction is directed toward the flow guide element (22).

5. The humidification system for a fuel cell according to claim 1 or 2, wherein: The humidifying system comprises a return unit (7) configured to be able to draw water from the spraying unit (1).

6. A fuel cell system, characterized in that: The fuel cell system includes the humidification system for a fuel cell according to any one of claims 1 to 5.

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